Material not linking properly?

I have a material “Wrought Iron” in a “materials.blend” file, and when I go to link it in another blend file, it has a different icon than all the other materials (here I duplicated it, thinking that might fix it, hence the number suffix):

And when I link it in, it creates a new Linked material called Wrought Iron, but isn’t the right texture (it’s actually “Chrome” from the same file). Why is this one not linking in properly? It’s only a matte black with a slight mirror to it at the moment (no bump or other textures, just the straight material).